77521551408 has 240 divisors, whose sum is σ = 250659552000. Its totient is φ = 21907791360.

The previous prime is 77521551397. The next prime is 77521551409. The reversal of 77521551408 is 80415512577.

77521551408 is a `hidden beast` number, since 7 + 7 + 52 + 1 + 551 + 40 + 8 = 666.

It is not an unprimeable number, because it can be changed into a prime (77521551409) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 50045418 + ... + 50046966.

It is an arithmetic number, because the mean of its divisors is an integer number (1044414800).

Almost surely, 2^77521551408 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77521551408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125329776000).

77521551408 is an abundant number, since it is smaller than the sum of its proper divisors (173138000592).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

77521551408 is a wasteful number, since it uses less digits than its factorization.

77521551408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2080 (or 2071 counting only the distinct ones).

The product of its (nonzero) digits is 392000, while the sum is 45.

The spelling of 77521551408 in words is "seventy-seven billion, five hundred twenty-one million, five hundred fifty-one thousand, four hundred eight".